Try to press simultaneously [control + alt + delete] (restart/reboot),
Next try, press simultaneously [ F2 + DEL], IF ayaw parin try to find a technical person na marunong mag open at mag detached ng hard disk, tapos yung tinanggal mo na hard disk data(Hitachi 320Gb) ay elagay mo sa isang sata enclosure at try mo gawing external hard disk drive at e insert mo sa ibang laptop/desk top, if ma read sya ang may problema ay yung window 7 os or yung unit na ginagamit nagkakaroon ng loose contact between sata terminal pin connectors dun sa unit.
If ever Hindi ma read yung Hitachi sata tru enclosure gmit as external drive sa ibang PC/laptop, ang may problema dun ay yung Hitachi 320Gb sata.